Plumbing Fixtures Metal Finishing and Buffing

Plumbing Fixtures:  Homeowners have long taken pride in building and remodeling their kitchens and bathrooms.  A central component of these rooms is the plumbing fixtures.  Over the past several years there has been an explosion of unique designs and finishes to fit an ever growing array of consumer tastes.  There are three primary base materials used the manufacture of plumbing fixtures: Brass, Zinc and Plastic.  The wide range of product designs, unique finishes and different base materials pose a unique challenge to the finishing process for plumbing fixtures.

Brass is most common in kitchen fixtures and may be made from tubing or machines brass stock.  Products from brass tubing often have a roughness or grain that is generated in the bending process that must be removed by buffing.  These round or oval parts lend themselves to mush buff applications to wrap around the curves.  Machined brass parts are often made from brass bar stock and the buffing machines need to remove the fine tool marks before they are plated.  The simple geometry of these parts often allows them to use the faster tangential buffing process with rotary buffing tables.

The low cost and high volume provided by zinc die cast operations makes Zinc common for bathroom fixtures and faucet handles.  Zinc allows for very complex geometries but usually has a thin outside skin that requires the less aggressive Mush Buffing Process to reduce the chance of buffing through the skin to the porous layer below. The porous layer has air pockets (seen as holes) that are very difficult to cover in the plating process and often requires scraping these parts when holes appear after buffing.  Most attempts to buff out the hole usually just drags out the hole (like a comet tail) instead of removing it.

Because both Zinc and Brass are prone to oxidation or corrosion they must be quickly plated or painted to maintain a bright, clean surface.  In the event that the queue is more than a 20 to 24 hours before being plated then it is possible to add an anti-corrosive to the buffing compound.  This additive will protect the surface from oxidation for several days or even weeks depending on temperature and humidity.